1. Field of the Invention
The present invention relates to garden tools, and more particularly to an apparatus for trimming vegetation, specifically one using a flexible line attached to a rotary device, generally similar to the tool popularly referred to as a "Weed-Eater." More generally, the invention pertains to a cutting head adapted for use with such a vegetation trimmer, wherein the cutting head feeds or dispenses the flexible line used to trim the vegetation.
2. Description of Related Art
Flexible line vegetation trimmers are known in the art, and are generally comprised of a long handle or rod having a cutting head at one end. The cutting head contains a spool of cutting line, similar to fishing line (polymeric monofilament), and a rotary device which causes the free end of the line to move in a circular fashion at high speed. When the cutting head is placed near overgrown vegetation, the spinning line hits the stalks or leaves and effectively cuts them away from the remainder of the plant. Flexible line vegetation trimmers have grown into a world-wide industry with annual sales exceeding a billion dollars.
One problem that has persisted with the use of flexible line trimmers (also referred to as rotary flails), is the dispensing of the cutting line from the spool. This line is typically constructed of a polymeric material that is relatively tough and durable but, after repeated use as a vegetation trimmer (or misuse on inappropriate surfaces), the line will break near the distal end, i.e., shortening the effective length of the line, and thus requiring replacement of the line, or extension of further line material from the spool.
In the prior art, there are four basic kinds of cutting heads: manual exchange; manual reel; semi-manual reel; and automatic reel. A manual exchange cutting head holds multiple lines which are not adjustable, but are instead completely removed and replaced when they get too short. The trimmer (rotary motor) must be stopped for replacement, and the stub ends are wasted. Additional material forming the mounting bracket for the lines is also discarded.
The reel types, whether manual, semi-automatic, or automatic, have a reel within a housing, and new line is delivered by releasing (rotating) this reel. With the manual reel type, the rotary motor must be stopped so the reel can be manually unlocked to extend new line. With the semi-automatic, feeding of new line is triggered by a hand lever or by bumping the cutting head on the ground. Manual and semi-automatic require the operator to monitor the line and decide when to take action. Another type of feeding device uses a mechanism which extends a length of line every time the rotary motor is slowed from a high operating speed.
The automatic reel types are equipped with a sensing device to monitor the line and activate a reel release or indexing mechanism to feed more line. A cycle of gradual decreases and sudden jumps in line length are an inherent feature because of the threshold for triggering the reel mechanism. Sudden jumps in line length cause wasted line, explaining the lack of commercial success of these types of cutting heads. Multiple independent automatic lines have been very impractical because of the complicated mechanisms involved. Today, almost all trimmers sold are equipped with bump feeds.
Reloading bump feeds is complicated and time-consuming. Casual users especially dislike the details of loading the line spool onto the cutting head. Even for those devices in which no disassembly or tools are required, it is still necessary to (i) bring the spool into loading alignment, (ii) insert the first cutting line into a loading hole, (iii) anchor the cutting line to the spool, (iv) repeat steps two and three for a second line, then (v) rotate the spool to draw the lines into the housing and wind them onto the spool. Bump feeds also have a tendency to jam. The bump button can get surrounded with mud, wet grass, or other bits of debris, and prevent proper dispensing of the line. Moreover, during feeding of a bump-type device, the head is subjected to sharp shocks which tend to jam the line in the coil and prevent smooth feeding of line. Clearing a jammed coil or bump button is time-consuming and can be further frustrating.
In light of the foregoing, it would be desirable to devise an improved method of dispensing cutting line from a vegetation trimmer. It would be particularly advantageous if the method utilized a cutting head that would rarely, if ever, jam nor need maintenance or adjustment, and was easily reloaded without tools or requiring disassembly.